Remotely releasable latching attachment for electromagnetic contactors



Feb. 24, 1959 H. E; SCHLEICHER REMOTELY-RELEASABLE LATCHING ATTACHMENT FOR ELECTROMAGNETIC CONTACTORS Filed Jan. 10, 1957 ALI/IA s4 United States PatentO REMOTELY RELEASABLE LATCHING ATTACH- MENT FOR ELECTROMAGNETIC CONTACTORS Harold E. Schleicher, West Hartford, Conn., assignor to The Arrow-Hart & Hegeman Electric Company, Hartford, 'Conn., a corporation of Connecticut Application January 10, 1957, Serial No. 633,468

' i 11 Claims. (Cl. 200-106) This inventionrelates to an attachment for electromagnetic contactors for latching the contactor in energized position; More particularly, it relates to an attachment which may be aflixed to existing electromagnetic contactorsv of whichthe contactor in my prior Patent 2,719,890 of October 4, 1955 is a typical example. The invention is not limited, however, to uses of the attachment with the particular structure illustrated in that patent, but is of more general utility.

There are occasions when it is undesirable for the coil of an electromagnetic contactor to remain energized because of the hum created and the power used and for other reasons. For such situations, it desirable to be able to have the contactor maintained in energized position by the provision of a latching device which acts automatically upon the contactor reaching fully energized position to hold the contactor in such position.

There are, nevertheless, occasions when it is desirable to have the contactor latched-in even though the solenoid of the contactor may remain energized.

Therefore, it is an object of the invention to provide a latching attachment for use in connection with electromagnetic contactors which will automatically maintain the contactor in energized position upon movement of the contactor to such energized position.

Another object of the invention is to provide an attachment of the foregoing type which may be released from a remote point by energization of a solenoid to trip the latching mechanism and permit the contactor to return to its deenergized position.

Another object of the invention is to provide in an attachment of the aforesaid type a remotely releasable latch which will not require an undue amount of current for its operation, but which by the inertia of the move mentof its plunger will trip the latch with a hammerblow and let the contactor return to deenergized position.

Another object is to provide a latching attachment of the aforesaid type which will hold the contact carriage at spaced points when latching the contactor in energized position, so as to prevent twisting and distortion of the operating mechanism while moving into and while in latched position.

Other objects and advantages of the invention will appear as the invention is described in connection with the accompanying drawing.

In the drawing:

Fig. 1 is a side elevation view, partly in longitudinal section, of a conventional electromagnetic contactor to which the invention has been applied, in energized position.

Fig. 2 is a fragmentary view of the parts illustrated in Fig. l but with the contactor in deenergized position.

Fig. 3 is a perspective view of the invention as applied to the contactor, in energized position.

In describing the invention, the attachment will be described as applied to an electromagnetically operated switch or contactor such as is disclosed in my prior Pat ent 2,719,890 to which reference may be hadfor a full disclosure of such a contactor.

Referring to the drawing, a base 10 of molded or other suitable insulating material is supported from a sheet metal back plate 11 by stamped sheet metal side plates 17 and 18 located at opposite sides of the device. On the top surface of the base fixed contacts (not visible) are mounted and are adapted to be engaged and disengaged by a bridging contact (not visible) which is mounted upon a contact carrier (not visible) moved by the electromagnetic operating mechanism of the device. I

The electromagnet and the actuating means connecting it with the movable contact carrier are located between the base and the back plate and" include a fieldpiece and solenoid coil (not visible) which causes movement of a T-shaped laminated armature 24.

The force of the armature is transmitted to a drive rod 32 which extends transversely between the side plates 17 and 18 parallel to the planes of the base and the back plate. Its ends are guided in elongated slots, such as 18s, punched in the side plates 17 and 18.

To transmit the force of the armature to the drive rod, a driving member 34 stamped of sheet metal and loosely pivotally secured to the armature is looped around the rod providing a non-rigid connection which allows rela tive lateral movement of the rod and loop 34. Near the opposite ends of the drive rods 32, similar stamped sheet metal driving links or bars such as 36b are mounted thereon. These driving links connect with operating mechanism, such as is described in my aforesaid prior patent, to cause operation of the movable contacts when the electromagnet is energized.

All of the foregoing relates to structure which is known and has been on the market for some time.

In order to automatically latch the armature and operating mechanism in energized position automatically, I have provided a novel attachment which may be secured to the base plate 11 by securing screws 51 passing through the base plate and threaded into a stamped sheet metal mounting plate 50 upon which the whole attachment is mounted. The attachment may be affixed or removed as a unit by screwing or unscrewing the screws 51. In my copending application Serial No. 645,120 filed March 11, 1957 is disclosed and claimed a remotely controllable electromagnetically operable latching unit which, like that herein described, may be attached 'to and removed from the electromagnetic contactor as a unit without disturbing the parts of the contactor itself.

In order that the attachment may be operated from a remote point to release the automatically operating latch (designated generally by the numeral 70 and more fully described hereinafter) an electromagnet is mounted upon the mounting plate 50. The electromagnet comprises a magnetically permeable cage consisting of a U-shaped stamped sheet metal member 52 between the arms of which is mounted a solenoid coil 53. The open end of the U-member 52 is closed by an L-shaped stamped sheet metal member 54 which is secured to the U-member by screws, rivets or other suitable means passing through a short leg of the L-member, such leg lying upon one of the arms of the U-membe For supporting the solenoid, a round tubular sleeve is providedbetween the ends of the cage formed by the members 52 and 54. A two-piece core is located within the sleeve 56, one piece 57 being afiixed to the long leg of the L-member 54 of the cage by riveting or in any other suitable fashion. The second piece 59 of the core is a movable plunger and is biased outwardly of the sleeve by a coiled compression spring 58 concentrically positioned within the sleeve and having its ends seated in coaxial bores in the two adjacent faces of the core pieces 57 and 59.

To pivotally support a latch member 70, a stamped sheet metal T-shaped bracket 60 is secured upon the upper arm of the U-member 52. The arms 61 and 62 of the bracket 60 extend laterally and oppositely toward the side plates 17 and 18, respectively, of the contactor and their ends 61a and 62a are bent down toward the base plate 11 in parallel planes.

Mounted in and extending transversely between and through the ends 61a and 62a is a pivot pin 64. On the extending ends of the pivot-pin 64 are pivotally mounted parallel arms 72 of the latch member 70 which may conveniently be stamped from sheet metal into the form illustrated in the drawing. The arms 72 extend in parallel planes obliquely upwardly from the transverse por-' tion of the latch 70 which connects said oblique arms. The arms 72 are parallel to the ends 61a and 62a of the T-bracket.

From the arms 72 of the latch member toward the drive rod 32 of the contactor project identical parallel extensions 72e and each has 'a nose 72n extending upwardly and a shoulder 72s extending horizontally as the device is viewed in the drawing. are adapted to embrace the lower outer quadrant of the drive rod 32 at spaced points.

In order to urge the latch member into position wherein it will automatically move into the position of Figs.

1 and 3 and hold the armature 24, the drive rod 32 and the associated parts in energized position, a coiled tension spring 75 is affixed at the middle of the transverse portion of the latch 70 while the other end of the spring is atfixed to the middle of the latch-supporting bracket 60.

When the contactor is deenergized, the parts occupy the position of Fig. 2 with the drive rod 32 lying in back of the nose 7211. When the armature 24 is attracted by energization of the contactor, it pulls the drive rod 32 along the guide slots 17s and 18s. This causes the rod to press down the latch as the rod rides upon and over the nose 72m requiring the latch to pivot in clockwise direction (as found in the drawing) against the bias of the spring 75. Upon reaching fully energized position, the rod 72 will have passed completely over the nose 7211 so that the latch may move counterclockwise into the position of Figs. 1 and 3, wherein it is held by the spring 75.

Devices of this sort are commonly mounted vertically; that is to say, with the back plate 11 against a vertical wall or support. Gravity or return springs (not visible), or both, urge the contactor armature 24 and drive rod 32 to return to the position of Fig. 2 when the armature 24 is not attracted.

' In order to disengage the latch 70 from a remote point by energization of the solenoid 53, the longer leg 81 of a J-shaped (Fig. l) tripping or trigger member 80 is riveted to the end of the plunger 59. The short leg 82 of this tripping member is located inwardly of the transverse portion of the latch member 70 so that when the plunger 59 is attracted, the leg 82 may move a short distance and then strike a transverse portion of the latch and continue thereafter under the urge of the attraction of the plunger 59. This causes pivoting in a clockwise direction of the latch member and disengages its noses 72;: from the drive rod 32, permitting the drive rod 32, armature 24 and as- ;ociated parts to return to the deenergized position of The axis of the pivot 64 of the latch 70 is located in the plane in which the drive rod 32 slides, in order to avoid release or rotation of the latch when in latching position (Figs. 1 and 3). In that position, the forces exerted on the latch pass through the pivot of the latch.

The latch spring 75 need only exert light pressure or bias on the latch and will not seriously add to the force which The shoulder and nose thus 2,875,294: i W I need be overcome by the solenoid 53 through plunger 59 and trigger 80.

Normally, friction between the drive rod 32 and latch noses 72. is sufficient to hold the parts latched-in after they have reached that position. Hence, only this friction and the counterclockwise component of the relatively light biasing spring 75 need be overcome by the tripping action of the trigger as it strikes the latch 70.

Many modifications within the scope of the invention will occur to those skilled in the art. Therefore, I do not limit the invention to the specific form and structure described.

What is claimed is:

1. An electric contactor having fixed and movable contacts, mechanism including a drive rod for moving said movable contacts, an electromagnet moving said drive rod laterally, in combination with an attachment for maintaining said mechanism in attracted position, said attachment comprising a pivoted latching member having arms engaging said rod at spaced points upon movement of said rod into energized position so as to avoid twisting of said rod and mechanism while latched by said latching member in attracted position, means biasing said latching member toward latching position, a tripping member engageable with said latching member to disengage said latching member from said rod, and an electromagnet for operating said tripping member.

2. An electric contactor having fixed and movable contacts, mechanism including a drive rod for moving said movable contacts, an electromagnet moving said drive rod laterally, in combination with a unitary attachment for maintaining said mechanism in attracted position, said attachment comprising a pivoted latching member having arms engaging said rod at spaced points along its length upon movement of said rod into energized position so as to avoid twisting of said rod and mechanism while latched by said latching member in attracted position, means biasing said latching member toward latching position, a tripping member engageable with said latching member to disengage said latching member from said rod, and an electromagnet for operating said tripping member, and supporting means for the attachment securable to and detachable from said contactor whereby the attachment may be securedand detached as a unit.

3. An electric contactor having fixed and movable contacts, mechanism including a drive rod for moving said movable contacts, an electromagnet moving said drive rod laterally, means guiding said drive rod for rectilinear movement in a plane, in combination with an attachment for maintaining said mechanism in attracted position, said attachment comprising a pivoted latching member having arms engaging said rod at spaced points along its length upon movement of said rod into energized position so as to avoid twisting of said rod and mechanism while latched by said latching member in attracted position, the pivot of said latching member lying in said plane, means biasing said latching member toward latching position, a tripping member engageable with said latching member to disengage said latching member from said rod, and an electromagnet for operating said tripping member.

4. An electric contactor having fixed and movable contacts, mechanism including a drive rod for moving said movable contacts, an electromagnet moving said drive rod laterally, means guiding said drive rod for rectilinear movement in a plane, in combination with a unitary attachment for maintaining said mechanism in attracted position, said attachment comprising a pivoted latching member having arms engaging said rod at spaced points along its length upon movement of said rod into energized position so as to avoid twisting of said rod and mechanism while latched by said latching member in attracted position, the pivot of said latching member lying in said plane, means biasing said latching member toward latching position, a tripping member engageable with said latching member to disengage said latching member from said rod, and an electromagnet for operating said tripping member, and supporting means for the attachment securable to and detachable from said contactor whereby the attachment may be secured and detached as a unit.

5. An electric contactor having fixed and movable contacts, mechanism including a drive rod for moving said movable contacts, an electromagnet moving said drive rod laterally, in combination with an attachment for maintaining said mechanism in attracted position, said attachment comprising a pivoted latching member having arms engaging said rod at spaced points along its length upon movement of said rod into energized position so as to avoid twisting of said rod and mechanism while latched by said latching member in attracted position, means biasing said latching member toward latching position, a tripping member engageable with said latching member to disengage said latching member from said rod, an electromagnet having a core-armature, said tripping member being mounted on said core-armature, means biasing said armature to hold said tripping member spaced from said latching member providing for lost motion upon attraction of said armature whereby said tripping member strikes said latching member with a hammer-blow.

6. An electric contactor having fixed and movable contacts, mechanism including a drive rod for moving said movable contacts, an electromagnet moving said drive rod laterally, in combination with an attachment for maintaining said mechanism in attracted position, said attachment comprising a pivoted latching member having arms engaging said rod at spaced points along its length upon movement of said rod into energized position so as to avoid twisting of said rod and mechanism while latched by said latching member in attracted position, means biasing said latching member toward latching position, a tripping member engageable with said latching member to disengage said latching member from said rod, an electromagnet having a core-armature, said tripping member being actuated by said armature, and means causing said tripping member to strike said latching member with a hammer-blow.

7. A device as claimed in claim 1 having means to cause said tripping member to strike said latching member with a hammer-blow.

8. An electric contactor having fixed and movable contacts, mechanism including a drive rod for moving said movable contacts, an electromagnet having a non-rigid connection with said drive red permitting relative motion therebetween, said electromagnet actuating said drive rod laterally, in combination with an attachment for maintaining said mechanism in attracted position, said attachment comprising a pivoted latching member engaging said rod in attracted position, means biasing said latching member toward latching position, a tripping member engageable with said latching member to disengage said latching member from said rod, and an electromagnet having a core-armature, said tripping member being actuated by said armature, and means causing said tripping member to strike said latching member with a hammer-blow.

9. A device as claimed in claim 3 having means to cause said tripping member to strike said latching member with a hammer-blow.

10. An electric contactor having fixed and movable contacts, mechanism including a drive rod for moving said movable contacts, an electromagnet moving said driving rod laterally, means guiding said drive rod for rectilinear movement in a plane, in combination with an attachment for maintaining said mechanism in attracted position, said attachment comprising a pivoted latching member, the pivot of said latching member lying in said plane, means biasing said latching member toward latching position, a tripping member engageable with said latching member to disengage said latching member from said rod, and an electromagnet having a core-armature, said tripping member being actuated by said armature, and means causing said tripping member to strike said latching member with a hammer-blow.

11. A device as claimed in claim 10 having supporting means for the attachment securable to and detachable from said contactor whereby the attachment may be secured and detached as a unit, said supporting means carrying said pivot of said latching member and locating it in the plane of movement of the drive rod.

References Cited in the file of this patent UNITED STATES PATENTS 

